西伯利亚鲟Sox9基因cDNA全长克隆、序列分析及其表达检测

为了研究Sox9基因在西伯利亚鲟侧线神经发育过程当中所起的调控作用,本研究利用RT-PCR和RACE方法获得了西伯利亚鲟Sox9基因cDNA全长序列,经序列分析表明,所克隆Sox9cDNA全长为1409bp,包括开放阅读框(open reading frame,ORF)1083bp,5′端非翻译区(untranslate dregion,UTR)19bp和3′端非翻译区(untranslate dregion,UTR)307bp。1083bp的ORF共编码360个氨基酸,相对分子质量为41221.7U。序列分析表明,其与施氏鲟的亲缘关系较近,其次是斑马鱼。经实时荧光定量PCR技术对西伯利亚鲟Sox9基因在各组织以及在胚胎发育各时期中的相对表达量检测发现,Sox9在西伯利亚鲟中的表达具明显的组织差异性和时间差异性。其中,在肝,肾,肌肉,胰中的相对表达量较低。然而,大脑组织中的表达量与以上4个组织相比,处于极高水平,达到胰脏中相对表达量8.9倍,达到表达量最低点肾脏中的近21倍。在胚胎发育的不同阶段,Sox9均有表达。在原肠期、神经胚期及视泡形成期,Sox9基因的表达量均较高,特别是在原肠期其表达量达到西伯利亚鲟...     

氟离子对西伯利亚鲟胚胎发育的影响

本试验在水温17±1℃的条件下,采用半静态式生物毒性试验方法,探讨了氟离子(F-)对西伯利亚鲟胚胎发育的影响。结果表明,100~600 mg/L氟暴露会导致胚胎孵化延迟,氟暴露组半数孵化时间(MHT)比对照组推迟9~22 h。氟暴露同时导致胚胎死亡率显著增加(P<0.05),出膜仔鱼活力减弱、存活时间缩短、畸形率显著升高(P<0.05),出现卵黄囊畸形、脊椎畸形、眼部充血等畸形症状。试验得出F-致西伯利亚鲟胚胎144 h半致死浓度(LC50)为447.61 mg/L,孵化安全浓度(SC)为4.48 mg/L,导致仔鱼畸形的半数效应浓度(EC50)为536 mg/L。氟对西伯利亚鲟胚胎的安全质量浓度低于我国部分高氟地区地下水、地表水及人为氟污染水域中氟含量,提示天然水体中氟可能会对鱼类胚胎产生负面影响,应引起重视。     

Effects of the dietary protein levels and the protein to energy ratio in sub‐yearling Persian sturgeon,Acipenser persicus (Borodin)

A 3 × 4 factorial design was used to evaluate the dietary protein requirement and to determine the optimum dietary protein to energy (P/DE) ratio in sub‐yearling Persian sturgeon, Acipenser persicus, reared in the indoor system. Twelve experimental diets (₄₀P₁₆, ₄₀P₁₇, ₄₀P₁₈, ₄₀P₁₉, ₄₅P₁₉, ₄₅P₁₇, ₄₅P₁₈, ₄₅P₁₉, ₅₀P₁₆, ₅₀P₁₇, ₅₀P₁₈ and ₅₀P₁₉) were formulated and prepared to contain three protein levels (40%, 45% and 50%) and four digestible energy levels (16, 17, 18 and 19 kJ g^?1 diet) at each protein level. Fish averaging 103.3 ± 3.5 (mean ± SD) were fed one of the experimental diets for 14 weeks. At the end of the experimental period, there were significant energy effects (P < 0.05) on weight gain (WG) and specific growth rate (SGR). Weight gain and SGR tended to decrease, although non‐significantly, with increase in dietary protein levels. Furthermore, there were significant protein and energy interaction effects on WG, SGR, hepatosomatic index and protein efficiency ratio. However, there were no significant dietary protein, energy or their interaction effects on feed efficiency for fish fed all diets. Weight gain and SGR of fish fed ₄₀P₁₉ were significantly higher than those of fish fed ₄₀P₁₆, ₄₅P₁₆, ₄₅P₁₇, ₅₀P₁₆ and ₅₀P₁₇ diets (P < 0.05). There were no significant differences in WG and SGR among fish fed ₄₀P₁₇, ₄₀P₁₈, ₄₀P₁₉, ₄₅P₁₈, ₄₅P₁₉, ₅₀P₁₈ and ₅₀P₁₉ diets. These results may indicate that the optimum dietary protein requirement and the P/DE ratio could be 40% protein and 22.0 mg protein kJ^?1 (₄₀P₁₈), respectively, in Persian sturgeon, based on growth performance and feed utilization.     

Novel droplet vitrification combined with fish antifreeze protein type III enhances cryoprotection of semen in wild endangered Persian sturgeon Acipenser persicus (Borodin, 1897)

In this study, the efficiency of a novel droplet vitrification technique along with different doses of fish antifreeze protein (AFP) type III on Persian sturgeon thawed spermatozoa quality (motility duration and motility percentage) was investigated. Semen of seven male individuals was pooled in equal volumes and diluted with 4°C Tris‐Hcl (100 mM), pH = 8 extenders containing 0, 5, 10, 15 μM of AFP type III in a ratio of 1:1 (semen/extenders). Treated semen was dropped into liquid nitrogen. Solidified droplets were stored for 2, 60 and 120 days and thawed by plunging them into a tube containing 5 mL Tris‐Hcl (100 mM), pH=8 with 1% BSA at 37°C. Motility duration in all treatments had no significant difference comparing to fresh sperm (P > 0.05), but their motility percentage was significantly lower. Treatment with 10 μM of AFP had significantly higher motility percentage (16.11 ± 0.5%) comparing to other treatments (P < 0.05). There was no significant difference between 0, 5, 15 μM of antifreeze protein treatments (P > 0.05), suggesting that antifreeze protein effectiveness are highly dose dependent, and dose of 10 μM is appropriate in Persian sturgeon spermatozoa droplet vitrification. Besides, the present technique obtained higher quality of spermatozoa comparing to its analogue techniques.     

大豆浓缩蛋白对中华鲟幼鱼生长、血脂和体成分的影响研究

分别用大豆浓缩蛋白(SPC)替代饲料中0(R0,对照组),15%(R15),30%(R30)和45%(R45)的鱼粉蛋白,配制成4组等氮等能饲料,喂养(58.00±2.69)g中华鲟(Acipenser sinensis)幼鱼10周,每组设3个重复,研究SPC对中华鲟幼鱼生长性能、饲料利用率,以及血脂和体成分的影响。结果显示,随替代比例的增加,中华鲟幼鱼的增重率(WG)、特定生长率(SGR)、饲料效率(FE)和蛋白质效率(PER)逐渐降低,肥满度和肝体指数无显著性差异(P>0.05)。FE在R30组出现显著差异(P<0.05),WG、SGR和PER在R45组出现显著性差异(P<0.05)。随替代比例的增加,血浆高密度脂蛋白胆固醇含量无显著变化(P>0.05),胆固醇(CHOL)、甘油三脂(TG)和低密度脂蛋白胆固醇(LDL-C)含量逐渐降低。CHOL、TG和LDL-C含量在R30组出现显著差异(P<0.05)。随替代比例的增加,肌肉和肝脏水分逐渐升高,脂肪逐渐降低,蛋白含量无显著差异(P>0.05)。R30和R45组的肌肉和肝脏水分含量显著高于R0组(P<0.05),脂肪含量显著低于R0组(P<0.05)。结果表明:在本试验条件下,综合考虑生长性能、饲料利用、血脂和体成分等指标,中华鲟幼鱼饲料中SPC替代鱼粉蛋白的比例可达30%。     

葛洲坝产卵场中华鲟繁殖群体数量与繁殖规模估算及其变动趋势分析

采用声学探测的方法,进行中华鲟(Acipenser sinensis)繁殖群体数量的估算.2005～2007年,第1次产卵前的资源量分别为235尾、217尾和203尾;第1次产卵后的资源量分别为157尾、157尾和102尾.采用食卵鱼解剖统计和股分析的方法对中华鲟的自然繁殖规模进行估算.其结果为,2005～2007年间中华鲟的产卵量分别为356万粒、119.6万粒和238.6万粒.结合历史相关研究数据,对近10年的中华鲟繁殖群体数量和繁殖规模的变动趋势进行分析,结果显示,在20世纪90年代中期,第1次产卵前的中华鲟繁殖群体数量下降趋势明显,但2002年以来其数量趋于基本稳定,年际间的差异没有统计学意义(P>0.05).自2002年以来,第1次产卵后停留产卵场的中华鲟数量有增加的趋势,而中华鲟的繁殖规模近10年来呈现极其显著性的下降趋势(P<0.01).     

盐度对俄罗斯鲟幼鱼血清渗透压、离子含量及鳃丝 Na+/K+-ATP 酶活力的影响

研究了急性盐度胁迫对7月龄俄罗斯鲟(Acipenser gueldenstaedtii)幼鱼[体质量(86.1±18)g]鳃丝Na+/K+-ATP酶活力、血清渗透压和血清离子(Na+、K+、Cl-)的影响。结果表明:幼鱼从淡水直接转入盐度15、20、25水中,96h死亡率分别为72.22%、100%、100%,其他组(盐度0、5、10)无死亡。各盐度组96h血清渗透压、Na+、Cl-浓度随盐度升高而增加,且各盐度组显著高于对照组(P0.05),盐度15组最高,盐度5、10组间各指标不存在显著差异(P0.05)。盐度组血清K+离子在48h中较对照组均显著降低(P0.05),96h时有所回升但仍低于对照组,盐度15与盐度5、10相比血清K+离子有显著性差异(P0.05),盐度5、10之间无显著性差异(P0.05)。盐度组鳃丝Na+/K+-ATP酶活力呈先下降后上升变化,48h为最低,与对照组有显著性差异(P0.05),96h时盐度5、10组鳃丝Na+/K+-ATP酶活力与对照组及组间无显著差异(P0.05),盐度15与对照组及盐度5、10均有显著差异(P0.05)。96h幼鱼的等渗点为303.2mOsm·kg-1,相当于盐度10.06,而Na+及Cl-等离子点分别为146.1mmol·L-1和136.8mmol·L-1,分别相当于盐度9.02和8.95。与盐度15组相比,盐度10及其以下处理组各项检测指标变化幅度相对较小,在幼鱼渗透调节范围之内,盐度10中养殖15d后各项指标与淡水组差异较小,因此7月龄俄罗斯鲟幼鱼已具备在盐度10及以下的咸水中生活的能力,但不能耐受高于10的盐度。